Real time aircraft tracking
The Flightradar24 app provides all the information about the aircraft in the sky. All of them? Not quite, military aircraft are not required to transmit via ADS-B. Because how does an app like Flightradar work? Commercial aircraft send their information via the mentioned system: "Automatic Dependent Surveillance-Broadcast". Thus, it gives the essential information of the aircraft in the air, so to speak. Flightradar has built a network around the world that collects and aggregates the information and makes it available on a map via an app and website. Unfortunately, the service has also often received sad notoriety because, of course, crashing aircraft also send the data and there is thus a publicly accessible archive of flight data of crashed flights. A restriction gives it technically conditionally then: In remote parts of the earth, especially where there is no land mass, there is also no data, because on the ground no station is available, which collects and evaluates these data.